Ketogenic Diets for Cancer
The Ketogenic Diet may help with the treatment of cancer, including brain tumors. Most of the available information comes from animal experiments, backed up with a few human case studies, but things look promising and human trials are occurring. There are even researchers who believe that the origin of cancer lies with metabolic abnormalities that lead to genetic problems rather than the genetic problems being the root cause. Note that while the Ketogenic Diet may help with a number of diseases, the Ketogenic Diet also has some health risks. There are no indications that the Ketogenic Diet is a viable alternative to existing, traditional treatments, but it may become an important way of improving the success of the current approaches.
1 How the Ketogenic Diet may help
There may be several mechanisms behind the effect of the ketogenic diet on cancer. Some may also apply to a lesser extent to other Low Carbohydrate Diets, but some require Ketones. It seems reasonable that the benefits of the ketogenic diet for cancer patients rely on multiple underlying mechanisms.
- The ketogenic diet typically reduces blood glucose levels, and high blood glucose is associated with tumor growth and reduced survival rates in cancer patients and animal models.
- Carbohydrate restriction lowers insulin and insulin-like growth factor (IGF) which directly stimulate tumor cell proliferation.
- Tumor cells are unable to metabolize ketones.
- Cancers promote the growth of new blood vessels, something the ketogenic diet inhibits, as Ketones are anti-angiogenic. This is also seen with calorie restriction, which reduces vascularity and increased apoptosis in mouse and human brain tumors.
- Cancer cells often don't undergo natural cell death, something the ketogenic diet enhances.
- Ketones may directly reduce the viability of cancer cells.
2 Animal Studies
There are a number of animal studies that have looked at the ketogenic diet and cancer. Some of these studies combine the ketogenic diet with calorie restriction, while others provide an unrestricted access to food, and some are simply based around complete fasting. Obviously animal studies do not necessarily apply well to humans, but the evidence is encouraging.
- The ketogenic diet may need to be combined with calorie restriction to ensure lowered glucose levels for the treatment of brain tumors. A study that compared an unrestricted standard diet, an unrestricted ketogenic diet and a restricted ketogenic diet in mice with implanted brain tumors, only the restricted ketogenic diet improved survival rates.
- The unrestricted ketogenic diet combined with Omega 3 and MCT delayed the growth of implanted gastric cancer cells in mice.
- Short term fasting can improve the survival rates for mice with implanted brain tumors, and this benefit can enhance both chemotherapy and radiation treatment.
- Drugs are being developed for cancer treatment that target metabolic pathways.
- Giving a no-carbohydrate ketogenic diet to rats with grafted prostate cancer tumors resulted in a 33% smaller tumor size than controls fed a western diet. In another study, rats with grafted prostate cancer tumors given 0%, 10% or 20% carbohydrate had similar survival rates.
- Rats with grafted prostate cancer tumors given a no-carbohydrate ketogenic diet (83% fat, 0% carbohydrate, 17% protein) had a better survival rate than those given a medium carbohydrate diet (40% fat, 43% carbohydrate, 17% protein), but their survival was similar to those given a low fat diet (12% fat, 71% carbohydrate, 17% protein).
- Rats with grafted lung cancer tumors showed that a ketogenic diet improved the effectiveness of radiation and chemotherapy.
- A study of Glioma tumor cells showed that an unrestricted ketogenic diet in mice that raised ketone levels without lowering glucose levels did not change survival rates.
- Rats with metastatic cancer had a 57% longer average survival time on the ketogenic diet than controls, and 78% longer when the ketogenic diet was combined with a hyperbaric oxygen therapy.
3 Human Case Studies
While I have not found any large studies of the ketogenic diet on humans, there are a number of smaller case studies that look promising.
- A case study of two children with inoperable Astrocytoma brain tumors that regressed under the ketogenic diet that lowered blood glucose levels is promising. This trial used the MCT Diet with 60% of calories from MCT, 20% from protein, 10% from carbohydrate, and 10% from other dietary fats, with total calories calculated at 120% of target to ensure weight gain.
- A study looked at the use of the Ketogenic Diet in 16 patients with advanced cancer and no other treatment options concluded that the diet was a suitable possibility and might improve some aspects of their quality of life. Not all the patients maintained the diet, with only 5 completing the 12 week study. Because of the low number of subjects and their heterogeneity, it was not possible to evaluate the impact of the diet on the tumors. However, the outcome for the 16 patients is intriguing:
- 4 patients dropped out early.
- 2 patients died early.
- 5 patients discontinued the diet and their disease progressed.
- 5 patients followed the diet and their disease was stable.
- A 65 year old woman with Glioblastoma multiforme (the most malignant primary brain tumor in adults and children) was treated with partial tumor resection and a combination of standard therapy and a restricted ketogenic diet. The diet was a calorie restricted (600 kcal/day) Ketogenic Ratio Diet (4:1) for two months, resulting in a 20% reduction in body weight. After the two months there were no discernable signs of the tumor with FDG-PET or MRI imaging. When a normal diet was resumed for 10 weeks there were signs of the tumor resurging on MRI scans. (See timeline of treatment below.)
- A (non-ketogenic) high fat diet may help maintain body weight and improve quality of life.
4 Non-Ketogenic Fat Intake and Cancer
There are a number of studies that have looked at the general relationship between fat intake and cancer. Omega 3 may help inhibit cancer, while Omega 6, and to a lesser extent saturated fats, may exacerbate cancer.
- Fat intake in a non-ketogenic diet impacts tumor growth.
- Omega 3 supplementation may improve the effectiveness of conventional chemotherapy and radiation therapy treatments of cancer, as well as directly impacting the tumor and metastasis.
- Omega-6 oils may increase tumor growth.
- Saturated fat tends to stimulate tumor growth, Omega-6 stimulates more than saturated fat, and Omega-3 inhibits growth.
- Omega-3 supplementation may reduce the risk of some cancers.
- In a study of 35,298 Singapore Chinese women aged 45-74 years, those with the lowest intake of fish Omega-3 had a 26% higher risk of breast cancer. For those with the lowest intake of Omega-3, the intake of Omega-6 was inversely related to their breast cancer risk. However, another study of 23,693 postmenopausal women showed that fish consumption increased the risk of estrogen receptor-positive breast cancer by 50% in those with the highest intake compared with the lowest. It has been suggested that this may be due to contamination with organochlorines or other endocrine disrupters in the fish. Other studies have found no relationship between fish intake and cancer.
- The results of trials with mono-unsaturated oils such as olive oils on tumor growth have been inconsistent.
- Restricting calories intake also impacts tumor growth, with 12% restriction reducing tumor growth in rodents.
- Even modest amounts of Omega-6 or saturated fat may negate the benefit of Omega-3.
5 Further Reading
In addition to the scientific papers referenced in this article, there are some books that may be useful.
5.1 Ketogenic Diets: Treatments for Epilepsy and Other Disorders
Ketogenic Diets: Treatments for Epilepsy and Other Disorders, by Eric H. Kossoff is the best all-around book I've come across on the ketogenic diet, and while it focuses heavily on epilepsy, it does touch on other conditions. If you are considering the Ketogenic Diet, I would consider this as essential reading. It has a positive view of the ketogenic diet, but balances this with the caution that comes with being a medical practitioner that has used the diet for many years.
Anticancer is a book by David Servan-Schreiber. In the book, David describes his personal battle with brain cancer, and the research he did to understand why we get cancer. The book presents a grim warning of the cancer epidemic that is occurring in the western world, with age-adjusted cancer rates steadily rising since the 1940s. However, the book also offers hope, as there are useful that may help fight cancer. Anticancer is an approach that may reduce our risk of getting cancer, and for those with the disease, it might supplement surgery, chemotherapy and radiation as treatments. The book claims that genes only comprise 15% of the risk for cancer, with smoking and diet contributing 30% each. There are several parts to the anticancer approach:
- The book suggests that the immune system forms a defense against cancer. If our immune system is compromised, then cancer can grow.
- Avoid high Glycemic Index foods. Having continuously elevated blood sugar and insulin levels causes chronic inflammation that compromises the immune system and provides growth hormones the fuel cancerous growth. High Glycemic Index foods are also linked to obesity, diabetes, and heart disease.
- Eat foods with anticancer properties, such as curry, green tea, soy, garlic. The book contains a longer list, and there is another book Foods to Fight Cancer with more information. I have not looked at the research that supports these foods.
- Boost Omega 3 intake and reduce Omega 6 intake, aiming for a 1:1 ratio of Omega-3 to Omega-6. This ratio is found in grass fed animal products, or it can be achieved through foods rich in Omega-3 such as fatty fish or Flax. All Trans Fats should be avoided (look for "partially hydrogenated" in the ingredients to identify trans fats).
- Detoxify by not consuming poisons. This primarily means eating more organic food, especially animal products such as meat or dairy. For non-animal products, some are worth getting organic, whereas others pose a more limited risk. There is a list of the 12 least contaminated and 12 most contaminated foods at The Dirty Dozen.
- Exercise for at least 20 to 30 minutes per day. The book notes that different types of cancers require different levels of exercise to achieve a comparable effect; for instance, colon cancer requires twice as much as breast cancer.
- Feelings of helplessness ( External Locus of Control) and past emotional traumas compromise our body's ability to fight cancer. For some, exercise can restore our feeling of control over our lives, but counseling may also be needed.
- Meditation, including yoga, tai chi, etc., helps reduce stress.
5.3 Cancer as a Metabolic Disease
This book, "Cancer as a Metabolic Disease: On the Origin, Management, and Prevention of Cancer" by Dr. Thomas Seyfried, is an expensive, technical book by one of the leading researchers in this field. It's recommended if you want to research more deeply into this topic. There is also a smaller and cheaper eBook called "Fight Cancer with a Ketogenic Diet" that is based on Seyfried's book.
6 See Also
- The classifications and types of Low Carbohydrate Diet.
- An introduction to the Ketogenic Diet.
- My experiences with ultrarunning on the Ketogenic Diet
- How the Ketogenic Diet can be used for the treatment and management of disease.
- Using the Ketogenic Diets to mitigate and treat Epilepsy
- How Ketogenic Diets might help with Cancer
- A look at the possible mechanisms of action of the Ketogenic Diet
- Health Risks of the Ketogenic Diet
- The time frame and changes that occur with Ketoadaptation
- What are Ketones
- The pros and cons of the Ketogenic Diet for athletes
- The Types of Ketogenic Diet
- How the Ketogenic Diet can be used for the treatment and management of disease.
- My Ketogenic Recipes
- Non-Ketogenic Low Carbohydrate Diets
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